The use of optical telecommunication systems, or networks, is growing and technology in this field is also improving. Optical telecommunication systems typically include a set of nodes which communicate with each other. In Dense Wavelength Division Multiplexing (DWDM) systems, light at multiple wavelengths is modulated with streams of digital information, and then the modulated light beams at different wavelengths, termed “wavelength channels”, are combined for joint propagation in an optical fiber.
To identify wavelength channels in a DWDM system, a pilot tone may be applied to communication channels within the optical telecommunications system. The pilot tone is typically a low frequency modulation of a wavelength channel's optical power level. The pilot tone carries information associated with the wavelength channel, such as, but not limited to, its wavelength and other identification information for supervisory, control, equalization, continuity, synchronization, or reference purposes.
By providing this pilot tone, communication between the transmitting node and the receiving node over the communication channel is improved as there is more information shared. The pilot tone also allows for data sharing between the different nodes within the optical telecommunications network. Detrimentally, the introduction of pilot tones requires a dedicated optical modulator or variable optical attenuator for each wavelength channel, which increases equipment cost and complexity, especially for optical communication systems carrying many wavelength channels.
Therefore, there is a need for an improved system and method for identifying wavelength channels in optical telecommunication systems.